1. Field of the Invention
The present invention generally relates to a computer based inventory evaluation system and, more particularly, to a system for automatically providing a manager with an estimate of inventory impact due to an introduction of an engineering change to an item in process. This item could be a new item or an old item used in an established product.
2. Description of the Prior Art
The process of designing, developing and manufacturing a new product, or making major changes to existing products, presents many challenges to product managers and manufacturing managers to bring a product to market for the least cost, within schedule while maintaining product quality. In today's highly competitive industries, product managers and manufacturing managers require information to address many problems that arise because of the complexity of new products and the complexity of world-wide production and the changing nature of competition. The requirement that products be manufactured for the least possible cost is important in all industries. Of all the costs associated with manufacturing a product, inventory cost is one of the primary costs, and all enterprises try to reduce this cost. Recent advances in manufacturing systems, utilizing proven Japanese techniques of production, which try to plan the arrival of all components and materials "just-in-time" to manufacture is a prime example of efforts to reduce inventory cost.
A number of books and articles have been published that address the issue of inventory costs. notably that industry reference Production-Inventory Systems, Planning and Control by Elwood S. Buffa, published by Richard D. Irwin, Inc., Homewood, Illinois, and Analysis of Inventory Systems by G. Hadley and T. M. Whitin, published by Prentice-Hall International, Inc., to name two. All systems to date refer to various types of rules for planning purposes in order to reduce inventory costs. When customers place demand for a product from a manufacturer, the planning department analyzes the demand and establishes inventory required to manufacture the product. That inventory, calculated through the bill of material is the component inventory or raw material inventory. In general, components are assembled together through various stages of the manufacturing process produce the finished product. All during the manufacturing process, labor and overhead costs are added to the raw material costs to compute the total cost of the product.
Customer demand for a product often changes over time, as do the specifications for the product as the product is improved or modified to realize economies in the manufacturing process. The engineering department normally releases engineering change notices (ECNs) reflecting changes to specifications of a given product. ECNs can be changes in the bill of material lists or component specification changes. When a significant change occurs, there can be work-in-process inventory or vendor committed components that may have to be discarded, with an attendant increase in manufacturing costs.
Many manufacturing systems are available in the market such as IBM Corp.'s COPICS (Communications Oriented Production Information and Control System) that provide an inventory accounting module which provides the capability to analyze inventory costs of all items in the warehouse or storage locations. Competing products marketed by MSA, Inc., Cullinet and others have similar capabilities but do not provide any means to evaluate total inventory cost impact due to engineering changes to a component.
What is needed is an automated system that automatically estimates the work-in-process costs of all affected in-process items as well as raw material item costs pertaining to an affected product. Such a system should take into account that a change to a single component may impact on multiple products in which the component is used. Preferrably, the system should be an expert system to provide an easy to use interface with a manager who needs to evaluate various options in effecting an engineering change notice. Expert systems are a branch of computer science, generally refered to as artificial intelligence, which exhibits characteristics normally associated with human behaviour including learning, reasoning, solving problems and so forth. More specifically, an expert system or "knowledge based system" uses certain rules and a database to provide a user interactive environment in the form of a "consultation dialog", just as the user would interact with a human expert.